Custom OS Template (Linux)

Although DaDesktop offers a variety of widely‑used Linux distributions, there may be times when you need a particular distro that isn’t included. For most mainstream Linux distros, DaDesktop is glad to assist. Just let us know where to grab the ISO file and which server you’d like to use for publishing the Custom OS template.

Important:

About Disk Partitioning
1. Your custom template should have either a single partition or two at most: one for EFI/Boot and another for the system and data.
2. LVM partitions aren’t supported—please avoid using LVM.
3. Using an incorrect partition layout will break disk auto‑resizing and other features.

Linux Template

After we’ve downloaded the ISO to the server, you’ll see it listed under Admin Menu->OS IMAGES->ISO FILES in your account.

Then you can set up the template via Admin Menu->OS IMAGES->CUSTOM OS TEMPLATES

Please follow these instructions closely and complete every step—otherwise, DaDesktop may not function properly.

Install the operating system.
Set the default username and password both to “student”.
Enable auto‑login for the “student” account.
Set the wallpaper to DaDesktop’s default or your own branded one
Some distros may now use Wayland by default as their display driver. Although Wayland works on DaDesktop, we suggest reverting to X11 for now.

To turn off Wayland:

Edit /etc/gdm/custom.conf, for example:
```
# Uncomment the line below to force the login screen to use Xorg
        WaylandEnable=false
        
```
Then log out and log back in.
Install spice‑vdagent—your package manager is usually the best route. It might already be installed depending on your distro.
- After a successful installation, restart the machine and confirm that two processes, spice‑vdagent and spice‑vdagentd, are running.
Install qemu‑guest‑agent—again, your package manager is the easiest approach.
Install X11VNC. For some distros, you might need to enable extra repositories, like the ‘epel’ repo for Red Hat‑based systems such as Oracle Linux or Rocky Linux.

Configure X11VNC

Ensure X11VNC is installed.
Open a root shell with sudo -i.

Run the command below to set X11VNC to auto‑start at boot.

cat > /etc/xdg/autostart/x11vnc.desktop <<EOF
                [Desktop Entry]
                Type=Application
                Exec=/usr/bin/x11vnc -N -no6 -rfbportv6 -1 -allow 10.0.3.1 -nopw -shared -alwaysshared -forever -repeat -nowireframe -noscr -nocursorshape -skip_lockkeys -cursor_drag -grab_buster -deferupdate 10 -speeds 6000,5000,20 -afteraccept announce-vnc-users.sh -gone announce-vnc-users.sh
                Hidden=false
                X-MATE-Autostart-enabled=true
                X-MATE-AutoRestart=true
                Name[en_US]=X11VNC
                Name=X11VNC
                Comment[en_US]=Share desktop over VNC
                Comment=Share desktop over VNC
                EOF

Create a desktop notification script by running these commands:

cat > /usr/local/bin/announce-vnc-users.sh <<EOF
        notify-send -a x11vnc "VNC users connected: $RFB_CLIENT_COUNT"
        EOF
        chmod +x /usr/local/bin/announce-vnc-users.sh

Restart the machine.
Make sure the firewall allows TCP port 5900—for example, using ss -pntl.

ss -pntl
Disable the sudo password prompt (recommended).
Verify success.

Connect to the machine. If the URL changes to include a token query parameter, everything is working—X11VNC is set up correctly. The text box at the bottom left of the screen, for copy‑paste between your local desktop and the virtual one, should now be functional.

Please Note

To enable additional optional features such as

DDWebdav, which syncs trainer content folders to each participant’s machine,
or DDUpload for effortless file uploads into a DaDesktop environment,

get in touch with DaDesktop Tech Support.